Resources

CHAPIS Emissions Maps

The California Air Resources Board has developed an
internet-based mapping tool that allows you to look at a map to view
sources of air pollution. We call this system CHAPIS (the Community
Health Air Pollution Information System). CHAPIS is about making
information regarding air pollution emissions available to you in ways
that are more understandable and more visual. The air pollutant
emission information contained in CHAPIS is provided for general
informational purposes. Please consult your local air district for the
most recent data available for specific facilities. The ARB should be
contacted regarding mobile source emissions.

The development of the information used in CHAPIS was a joint effort
between the ARB and the State's 35 local air pollution control or air
quality management districts. Districts provide the data for facilities
in their jurisdiction. Everyone contributing to the CHAPIS system has
made a major effort to make information in CHAPIS as accurate as
possible. However, as with any system that is using millions of pieces
of information coming from multiple sources, we anticipate that users
may find some information that is not up-to-date or is not accurate. In
addition, please keep in mind that due to the way emission information
is reported, collected, and managed, there can be a substantial lag
time between when the emissions occurred and the reporting of the
information to the local air districts' and ARB's emission inventory
databases.

Currently, most of the data are from 2001, although some of the data
about toxic emissions can be from various years from 1990 to 2001 (see
more discussion of the Air Toxics "Hot Spots" program below). ARB will
be making regular updates to CHAPIS to correct data problems as they
are brought to our attention. We encourage everyone to make use of our
"Email Comments" link at the bottom of the maps to bring any data
problems to our attention.

What can
CHAPIS do?

You can use these maps to answer questions like:
What are the major sources of air pollution within several miles of my
home? What are the relative contributions of mobile sources and
stationary sources? What sources are near my son or daughter's school?
Which chemicals are emitted by a particular facility or mobile sources
in this area? To answer these questions you must provide CHAPIS with a
location of interest (e.g., county or zip code) and choose which types
and sources of pollution you would like to explore.

From the CHAPIS map there are also links to other data sources, such as
tools to query the statewide emission inventory database and the
network of air monitoring stations.

The air pollutant emission information contained in CHAPIS is provided
for general informational purposes only. Please consult your local air
district for the most recent data available for specific facilities. In
addition, please see the discussion of data limitations in the "What
are the limitations?" section below.

What are the limitations?

Please keep
in mind that there are limitations to CHAPIS, and ways to use
it most effectively. We have tried to provide helpful background
information in the CHAPIS Help links, the on-line
Tutorial, the FAQ link, as well as on the next pages. Some of the key
things to note include the following.

(1) Emissions Are Not the Same as Exposure: Please keep in
mind that the emissions alone do not fully represent where and what
extent
of exposures to air pollution or possible health risks may occur.
Weather and wind can result in exposures that
occur in different locations from where the emissions actually
occurred, and can create new pollutants due to chemical
reactions in the atmosphere. Also, a larger number for emissions of a
particular chemical may not be as important
as smaller amounts of more potent chemicals. While air pollutant
emissions information can serve as an indicator
of local air pollution, it is the exposure to emissions that influences
health effects. Exposure is the amount
of pollution that someone actually breathes or otherwise ingests at
different locations. Exposure varies with how
far away the source is, how the emissions are released into the air and
dispersed by the wind, and in what locations
a person spends their time doing various activities. Exposure to air
pollutants can also occur from indoor sources
such as cooking, cleaning, and smoking; however, CHAPIS does not
address the contribution of indoor sources. The
importance of the exposure to health risk also depends on the
combination of multiple air pollutants, the relative
toxicity of the pollutants, and many other factors. The CHAPIS web tool
does not map the exposure levels or the
health risks associated with the pollutants and sources it tracks. (See
more discussion of exposure on the next
page.)

(2) CHAPIS Does Not Contain All Air Pollution Sources
Or All Air
Pollutants: It is important to keep in mind that CHAPIS does
not contain information on every source of air pollution and does not
show every chemical emitted. CHAPIS is being
developed in stages to assure data quality. For example, cars and
trucks are covered in the gridded mobile emissions
for many criteria and toxic pollutants, but they can emit additional
pollutants (e.g., PAHs) that are not covered
at this time due to lack of data. Large industries and small businesses
are being phased in by categories of facilities
to ensure quality. The initial release of CHAPIS includes about 2,000
large industrial and small commercial facilities.
The initial release covers facilities emitting the bulk of the criteria
pollutant (smog-forming) emissions and
many of the larger or important sources of toxic air pollutants.
However, overall at this time, there is a much
lower number of facilities with toxic air pollutant information in
CHAPIS than for criteria pollutants. It is a
major objective of CHAPIS to include all of the largest air pollution
sources and those with the highest documented
air pollution risk. CHAPIS will be updated on a periodic basis and
additional facilities will be added to CHAPIS
as more data become available.

(3) Emission Estimates Are Based on Average Conditions: CHAPIS is intended
to provide a visual, map-based window into the ARB's emission
inventory database. The emission inventory covers routine, annual air
pollution emissions. Process upsets and accidental
releases are not included.

(4) Emission Estimates Are Based on a Variety of
Factors and Assumptions,
and Are Not Exact Measurements of Emissions: Emission
inventories
provide estimates of the air pollution released from sources but are
not an exact accounting of actual amounts.
Emission estimates are based on overall average conditions (not any
specific day), and are generally based on a
limited number of source tests, available emission factors, or material
balance calculations for similar types
of sources. The exact locations of the releases may not be reflected in
detail, nor the types of stacks or other
release characteristics that influence how the emissions may affect
downwind areas.

(5) Industrial and Commercial Facilities Are Not the
Only Sources
of Air Pollution: While the locations of industrial and commercial
facilities appear on the CHAPIS maps, they are not the only sources of
air pollution. Cars and trucks are responsible
for most of the air pollution in the State, and generally pose the most
prevalent health risks. CHAPIS has tools
to show the combined contributions of cars and trucks, together with
other sources like industrial sites, using
what we call the gridded emissions. The Gridded Emissions options
provide a way to see the combined effects of
all types of sources reported for a given air pollutant within a series
of square grid cells covering an area.
(Depending on how much the user zooms in, the size of the grid cells
will be either 4 km x 4 km cells, or 1 km
x 1 km cells.) The "Calculate Combined Stat(istic)s" feature further
provides a summary list and bar
chart for all the grid cells in the entire map viewing region.

(6) Choosing a Pollutant:
The CHAPIS maps can only symbolize the emissions of one air pollutant
choice at a time. However, users can then
use the "Identify" or "Calculate Stats" tools to hyperlink to the ARB's
underlying emission
inventory database for more information about each facility. In
addition, there are several pick-list choices under
"Select pollutant" that provide combined values (e.g., All Toxic
Compounds, Other, and Potency-Weighted
Lbs).

(7) Informational Purposes:
The air pollutant emission information contained in CHAPIS is provided
for general informational purposes only.
Please consult your local air district for the most recent data
available for specific facilities.

Browser
Tips
CHAPIS is best viewed using Internet Explorer (version 5 or higher).
Netscape Navigator (version 4.6 or higher)
is also generally satisfactory. CHAPIS uses pop-up windows to display
some results, so pop-up blockers should be
disabled. For best results, use a screen setting of 1024 x 768 pixels,
and use a "Text Size" setting
of Medium (or Small), to ensure that all buttons will be visible
without excessive scrolling or re-sizing of windows.
The next pages provide tips for new users, as well as links to learn
what actions are underway to reduce air pollution
and toxic risks. Click on CONTINUE to learn more about what you can do
in CHAPIS.

What
information does CHAPIS have now?

We have already included a large amount of
information in this first release of the CHAPIS tool for you to view,
and there will be more over time. CHAPIS includes all the available
data for mobile sources (cars and trucks, and off-road equipment) and
area-wide sources, as well as about 2,000 large industries and small
businesses (stationary source facilities). The initial release includes
facilities emitting the bulk of the criteria pollutant (smog-forming)
emissions and many of the larger or important sources of toxic air
pollutants. However, overall at this time, there is a much lower number
of facilities with toxic air pollutant information in CHAPIS than for
criteria pollutants. We are phasing-in the industries and businesses by
categories of facilities to help ensure that the information we provide
is as accurate as possible. We are working closely with the local air
districts.

For criteria (smog-forming) pollutants, facilities
that emit 10 or more tons per year of nitrogen oxides, sulfur oxides,
carbon monoxide, PM10, or reactive organic gases are included. For
toxic pollutants, facilities are being phased in by categories in
collaboration with the local air districts. Large facilities including
petroleum refineries and power plants of 50 megawatts or more are
included, as well as facilities that conducted health risk assessments
under California's Air Toxics "Hot Spots" program in the categories of
chemical manufacturing, metal fabrication, and aerospace/electronics
manufacturing. In the future, the remaining "Hot Spots" risk assessment
facilities and other industries and smaller businesses, such as gas
stations and dry cleaners, will also be added.